Corzine was a senior partner at the Wall Street giant before being elected to the Senate in 2000, while Gensler spent 18 years at the firm. Corzine, who was defeated in his bid for a second term as New Jersey's governor in 2010, was the chairman and CEO of MF Global until it imploded last month.

With Gensler out of the country, the CFTC is being represented at Thursday's hearing of the House Agriculture Committee on MF Global's bankruptcy, by Jill Sommers, the senior commissioner at the agency.

Johnson complained that Gensler, because of his ties to Corzine through Goldman Sachs, has recused himself from anything to do with MF Global, including congressional oversight hearings.

"I find that entirely unacceptable," Johnson said. The Illinois Republican called the two men "part of the Goldman Sachs' fraternity."

But Rep. Collin Peterson (D-Minn.), the ranking member of the Agriculture Committee, interrupted Johnson to say that Gensler recused himself from the MF Global case because he was asked to by Sen. Chuck Grassley (R-Iowa).